As the disease progresses, people with Alzheimer's will need more support from those who care for them. Eventually, after several years, they will need help with all their daily activities. However, each person is affected in a particular way, and no two people experience Alzheimer's disease in exactly the same way.

Alzheimer's is a progressive disease, which means that gradually, over time, more parts of the brain are damaged. As this happens, the symptoms become more severe.

It must be emphasized that the early symptoms are well within the normal range of forgetfulness. It is inevitable that anyone reading this may wonder whether they have the condition. However, it is much more likely that you are as forgetful in an entirely normal way, just like the professor who has written this!

Does Alzheimer's disease only happen to elderly people?

Alzheimer's is not restricted to elderly people: in the UK, there are at least 15,000 people under the age of 65 with dementia. However, age is the greatest risk factor for dementia. Dementia affects one in 14 people over the age of 65 and one in six over the age of 80.

Does Alzheimer's disease happen in families?

Many people fear that they may inherit Alzheimer's disease. However, in the vast majority of cases the effect of inheritance seems to be small. If a parent or other relative has the disease, your own chances of developing it are only a little higher than if there were no cases of Alzheimer's in the immediate family. Carriers of the ApoE4 gene variant have a higher chance of developing Alzheimer's disease.

There are a few families where there is a very clear inheritance of the disease from one generation to the next. This is often in families where the disease appears relatively early in life. A number of genes which appear to cause Alzheimer’s in these families have been identified, though they are in general a rare cause of the illness.

What else is known about Alzheimer's disease?

People who have had severe head injuries also appear to be at increased risk of developing dementia. Boxers who receive continual blows to the head are at risk too. Possibly Charlie’s skill in heading the old type of heavy leather cased football may have brought the condition on earlier.

People who smoke, and those who have high blood pressure or high cholesterol levels, increase their risk of developing Alzheimer's.

So far, no one single factor has been identified as a cause for Alzheimer's disease. A combination of factors (including age, genetic inheritance, environmental factors, diet and overall general health) are likely to be responsible in any one person. In some people, the disease may develop silently for many years before symptoms appear and the onset of clinical disease may require a trigger such as a bad fall.

Getting a diagnosis

If you are concerned about your own health, or the health of someone close to you, it is important to seek medical help.

There is no straightforward test for Alzheimer's disease or for any other cause of dementia. A diagnosis is usually made by excluding other causes which present similar symptoms. The doctor will need to rule out conditions such as vitamin deficiency, thyroid problems, depression, brain tumours and the side-effects of drugs.

A specialist may be asked by your GP for help in diagnosis. The specialist may be an old-age psychiatrist, a neurologist, a physician in geriatric medicine or a general psychiatrist.

A full physical examination and blood tests will be needed to rule out or identify any other medical problems. The person's memory will be assessed, initially with questions about recent events and past memories. Memory and thinking skills may also be tested by a psychologist using detailed tests.

A brain scan may be carried out to give some clues about the changes taking place in the person's brain. There are a number of different types of scan for clinical diagnosis, including computerised tomography (CT) and magnetic resonance imaging (MRI).

Treatment

There is currently no cure for Alzheimer's disease. However, some drug treatments are available that can ameliorate the symptoms or slow down the disease progression in some people.

So far we know that people with Alzheimer's have a shortage of acetylcholine in their brains. The drugs Aricept, Exelon and Reminyl (trade names for the drugs donepezil hydrochloride, rivastigmine and galantamine, respectively) work by maintaining the levels of acetylcholine. These drugs are available to people in the moderate stages of dementia, and at your GP's discretion, for people in the early stages. A drug called Ebixa (trade name for the drug memantine) works in a different way to the other three − it prevents the excess entry of calcium ions into brain cells. Excess calcium in the brain cells damages them and prevents them from receiving messages from other brain cells. Ebixa is the only drug that is suitable for use in people in the middle to later stages of dementia.

The National Institute for Clinical Excellence (NICE) guidelines state what is available for which indication in the UK.

There is no cure at the present time, but the available drugs may slow the progress of Alzheimer's disease.

How about other kinds of dementia?

Vascular dementia is caused by damage to the blood vessels supplying the brain. It is the second commonest form of dementia.

Dementia with Lewy bodies is a form of dementia which accounts for around 15% of all cases of dementia in older people but is often goes unrecognised. The name refers to tiny, spherical protein deposits found in nerve cells. Their presence in the brain disrupts the brain's normal functioning, interrupting the action of important chemical messengers, including acetylcholine and dopamine.

Lewy bodies are also found in the brains of people with Parkinson's disease, a progressive neurological disease that affects movement. Some people who are initially diagnosed with Parkinson's disease later go on to develop a dementia that closely resembles DLB.

There are several much rarer forms of dementia. Information can be found on the Alzheimer’s Society website.